In Windows 2008 R2 , Microsoft changed the location of some polices. one of the change affected the place of adjustment of Screen lock policies
Now it is under: User Configuration>Policies>Administrative Template>Control Panel>Presonalization
The policies that you need to adjust are :
- Enable Screen Saver
- Prevent Changing Screen Saaver
- Password Protect The Screen Saver
- Screen saver Timeout
Note: Remember that policy is applyed to users, not computers.